An analysis of microstrip with rectangular and trapezoidal conductor cross sections

The finite-difference time-domain (FDTD) technique is used to analyze boxed microstrip with both rectangular and trapezoidal cross sections. It is confirmed that the exact shape of the conductor has a marked effect on the effective permittivity of the microstrip. Results using this method are compared to the findings of K.A. Michalski et al. (1989) using the analytically more complicated boundary element method; very good agreement is observed. The effect of adding a thin passivation layer is also calculated and it is found that such an addition noticeably reduces the effective permittivity of the microstrip. It is shown that the FDTD technique is capable of treating microstrip with a general cross section and producing accurate results.<
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